The objective of this proposal is to test the hypothesis that altered activities of certain glycosyltransferases in respiratory epithelium are responsible for longer carbohydrate chains and higher sulfate content of mucous glycoproteins (MGP) secreted by respiratory epithelium in cystic fibrosis (CF). Microsomal preparations of tracheobronchial and nasal epithelium from patients with CF, chronic bronchitis, other hypersecretory states and from individuals with no known respiratory tract disease (normal) will serve as sources of glycosyltransferases. Molecules with well-defined structure will be used as the glycosyltransferase acceptors for the radioactively labeled sugars from sugar nucleotide substrates. The reaction product of each glycosyltransferase will be characterized with respect to the identity of the transferred sugar, site and linkage of the transferred sugar, and anomeric configuration of the newly-formed glycosidic bond. Specific activities of fucosyl-, galactosyl-, N-acetylglucosaminyl-, n-acetylgalactosaminyl-, and sialyltransferases from each source will be statistically analyzed to determine whether levels of any of these enzymes are perturbed in disease states. Further comparisons will be made for ratios of both galactosyl- and N-acetylglucosaminyltransferase activities to activities of both fucosyl- and sialyltransferase (using a single acceptor for each pair) as a function of tissue source. Alterations of any of these ratios will be confirmed by measuring activities of each pair of transferases, e.g., galactosyl/fucosyl transferase, in an assay mixture where both are competing for the same acceptor. Whenever glycosyltransferase activities are altered, the enzyme in question will be characterized with respect to pH optima, Km, Vmax, heat stability, and for responsiveness to polycationic compounds. These studies are expected to show that the relative levels of galactoxyl- and N-actylglucosaminyltransferases, which theoretically act to lengthen carbohydrate chains, are elevated in CF epithelia. Further more, these studies will provide information concerning regulation of oligosaccharide chain synthesis for human respiratory MGP, which may be useful for the future development of more effective treatment of patients with CF and other obstructive lung diseases.